Modern paintball guns are generally capable of operating at high rates of fire. At high rates of fire, even when electronic sensors and other sophisticated equipment are used to prevent ball breaks in the breech of the paintball gun, ball breaks may occasionally occur. The internal paintball gun chambers and components may also need routine maintenance and/or lubrication. When a ball breaks in the breech of the paintball gun, or when other cleaning or servicing of the internal pneumatic components needs to take place, a bolt and/or other pneumatic components of the paintball gun must generally be removed to gain access to the breech and the internal pneumatic components of the paintball gun. Although quick-removal bolt assemblies, such as that shown in U.S. Pat. No. 7,237,544, have been provided for a number of years for stacked-tube design paintball guns, quick removal solutions for single-bore or spool-valve designs have been more complicated to provide. Although some prior art solutions provide a rearwardly removable pneumatic assembly in a spool-valve design, these mechanisms generally require that the pneumatic assembly be unthreaded from the paintball gun bore after the gun has been degassed and may therefore have a more complicated removal process than desirable.